I can't say for sure how Rob balances the scenarios for this group (I believe he at least uses BV as a starting point). My home group in Columbus almost never uses BV. I personally think that its not accurate enough for how complex it is. While BV does a good job balancing stand up fights between similar units (i.e. one lance of battlemechs vs. one lance of battlemechs), it isn't so great at balancing fights between more asymmetrical forces (different number of units and different type of units on each side). BV also has no way to account for differences in terrain, scenario, and composition of the remainder of the force, all of which can greatly influence a unit's effectiveness. For example, infantry is almost completely useless in a battle taking place in an open field, but can be a nightmare to deal with in a city. As a result, my home group simply eyeballs balance most of the time for more complex scenarios. If its just a quick lance vs. lance game, then we usually just roll up units on a RAT (after agreeing on a set number of mechs of each weight class) as we enjoy trying to win with less optimized designs.
If you guys are just running lance vs. lance engagements, then BV does do a pretty good job of keeping things balanced. I would say 5,000-6,000 BV is reasonable for an inner sphere lance if you want 4/5 pilots and medium to heavy mechs. Feel free to increase that to 8,000-10,000 BV if you guys like heavier mechs and better pilots. 10,000 BV is a good starting point for a Clan Star. Again, if you want better pilots or heavier units, then 15,000 BV to 20,000 BV can be more appropriate for a clan force.